The malfunctioning of protein kinases (PKs) is the hallmark of numerous diseases. A large share of the oncogenes and proto-oncogenes involved in human cancers code for PKs. The enhanced activities of PKs are also implicated in many non-malignant diseases, such as benign prostate hyperplasia, familial adenomatosis, polyposis, neuro-fibromatosis, psoriasis, vascular smooth cell proliferation associated with atherosclerosis, pulmonary fibrosis, arthritis glomerulonephritis and post-surgical stenosis and restenosis.
PKs are also implicated in inflammatory conditions and in the multiplication of viruses and parasites. PKs may also play a major role in the pathogenesis and development of neurodegenerative disorders.
For a general reference to PKs malfunctioning or disregulation see, for instance, Current Opinion in Chemical Biology 1999, 3, 459-465.
Among the several protein kinases known in the art as being implicated in the growth of cancer cells are Aurora kinases, in particular Aurora-2.
Aurora-2 was found to be over-expressed in a number of different tumor types. Its gene locus maps at 20q13, a chromosomal region frequently amplified in many cancers, including breast [Cancer Res. 1999, 59(9), 2041-4] and colon.
20q13 amplification correlates with poor prognosis in patients with node-negative breast cancer and increased Aurora-2 expression is indicative of poor prognosis and decreased survival time in bladder cancer patients [J. Natl. Cancer Inst., 2002, 94(17), 1320-9]. For a general reference to Aurora-2 role in the abnormal centrosome function in cancer see also Molecular Cancer Therapeutics, 2003, 2, 589-595.
The insulin-like growth factor 1 receptor (IGF-1R, IGF1R) is a member of the insulin receptor subfamily of RTKs.
There exist several lines of evidence suggesting that IGF-1R signaling can contribute to tumor genesis, and that interfering with IGF-1R function represents a valid therapeutic option in cancer. Forced expression of the receptor leads to ligand-dependent transformed growth of murine and of rat fibroblasts (e.g. Kaleko M., Rutter W. J. and Miller A. D. Mol Cell Biol vol. 10, pages 464-73, 1990; Rubini M., Hongo A., D'Ambrosio C. and Baserga R. Exp Cell Res vol. 230, pages 284-92, 1997), and such transformed cells are able to form tumors in vivo, with both in vitro transformation and tumor formation in vivo being dependent upon an active kinase domain (reviewed in Blakesley V. A., Stannard B. S., Kalebic T., Helman L. J., and LeRoith D. J Endocrinol vol. 152, pages 339-44, 1997).